Gripping means for a signal line and signal line

ABSTRACT

The invention relates to a gripping means for a signal line, which signal line is embodied such that the signal transmitted through the line can be influenced by loads exerted externally on the cable, which gripping means comprise at least one rigid component adapted to grip the sleeve of the signal line, wherein the gripping means also comprise a spring element engaging on the rigid component to remove the load of the rigid component from the signal line. The invention also relates to a signal line embodied such that a signal transmitted through the line can be influenced by loads exerted externally on the cable.

The invention relates to gripping means for a signal line according tothe preamble of claim 1. The invention also relates to a signal lineaccording to the preamble of claim 14.

The use of lines to carry signals, by transmitting a signal therethroughand by then measuring this signal in order to thus detect whether achange has occurred in the external load (particularly pressure) of theline, is known. Line sensors of this type make use of changes in thewavelength of a signal transported through a line as a consequence ofexternal loads exerted upon the line during the signal transport.Reference is made here to the International patent applicationPCT/NL97/00693, which describes a light-transmitting cable with which anexternal load can be detected. In addition to the use of for exampleglass fibre or synthetic fibre for transporting-light of the visiblespectrum (for example 180-800 nm), it is also possible in this contextto envisage an even broader spectrum of electromagnetic radiation incombination with lines adapted for passage of such radiation. There areno restrictions in respect of the minimal or maximal diameter of theline. A drawback of the existing lines for this application is that theyare usually wrapped around a core (tube) with crossing patterns, wherebythe greatest sensitivity occurs at the positions where the cablecrosses. A significant drawback is the relatively voluminous andexpensive structure that must therefore be arranged (usually built in)at a location to be monitored. An additional drawback of such astructure is that the maximum length of a sensor (the length to bemonitored) is considerably decreased due to the structure.

The present invention has for its object to provide a solution withwhich the sensitivity of a signal-carrying line can be increased insimple manner and with which the above stated drawbacks of the prior artcan be avoided.

To this end the invention provides gripping means of the type stated inthe preamble with the feature that the gripping means also comprise aspring element engaging on the rigid component to remove the load of therigid component from the signal line. The phrase ‘removing the load’ ishere understood to mean at least partially removing the load exerted bythe rigid component on the signal line, at least in a situation wherethe rigid component is not externally loaded, or only loaded to alimited extent. In an unloaded situation of the signal line a signal isthus not influenced, or less so, by the at least one more rigidcomponent. An important advantage hereof is that the signal line canhave a greater length than a comparable signal line with comparableperipheral equipment according to the prior art. Because the signal willnot be distorted (or at least less so than according to the prior art),the reliability of an application of the signal line is also increasedrelative to the existing applications. The spring element is preferablyadapted here to exert a biasing force on the rigid component anddirected away from the signal line when the rigid component is displacedto the signal line, so that the rigid component is pushed away from thesignal line.

European patent application EP 0 419 267 describes an optical sensorcontrol system that makes use of an optical cable sensitive to aninternal pressure P. The invention focuses more specifically on thesignals utilized in such a system. Serrated (corrugated) elements arealso shown whereby external pressure can be transmitted to the opticalcable. There is no reference to means for forcing apart these serratedelements in the unloaded state thereof.

The spring element can be manufactured from a flexible material, such asfor instance a flexible plastic or (synthetic) rubber. On the other handit is also possible to use other types of spring, such as for example ametal spring. In a specific preferred variant, the spring element isembodied as a resilient sleeve in which at least one rigid component isplaced. When it supports on a form-retaining (hard) object, theresilient sleeve will function as a spring element. In another preferredvariant the spring element is placed between two rigid components to bepushed apart by the spring element, wherein the signal line can then beplaced between the components. With such a ‘switch’, the rigidcomponents will be pushed apart in an unloaded situation such that theywill exert no load (or only a limited one) on the signal line.

If the gripping means are provided with connecting means, an optionallyreleasable coupling can be realized between the gripping means and thesignal line. The advantage of such a coupling is that the relativeorientation of gripping means and signal line is thus made manageable,and thereby also the effect of the gripping means on the signal line.

The rigid component preferably has a hardness of between 10 and 100Shore (for example hardness Shore A or Shore D), even more preferably ahardness between 25 and 75 Shore. A for instance more or less sharpcontact edge of the rigid component that lies against the signal linewill form a location where the sensitivity of the signal line is great.Another advantage is that a signal-carrying cable can be built in veryeasily because of the present invention; a construction that isvoluminous and difficult to assemble is after all unnecessary. It willbe apparent that this also results in a more economical application of apressure-sensitive signal line. Yet another advantage is that thelocations where the line is most sensitive can be determined veryprecisely.

In an advantageous embodiment variant of the gripping means, the edge ofthe rigid component connects to the spring element, preferably acomponent with a hardness less than 60 Shore, even more preferably lessthan 40 Shore (for example hardness Shore A or Shore D). By way of thisembodiment variant it becomes possible for instance to combine aplurality of rigid components with each other with softer componentstherebetween; the gripping means can therefore comprise a large numberof edges which result in increased sensitivity.

In yet another preferred variant, the gripping means are positioned suchthat an edge of the rigid component is at least substantially at rightangles to the centre line of the signal line. This results in a highdegree of sensitivity of the signal line.

The gripping means can be releasable from the signal line such that theycan be connected to the signal line at a position where sensitivity isdesired. It is also possible to change the locations with relativelyhigh sensitivity by displacing the gripping means. On the other hand itis also possible for the gripping means to be combined, at leastpartially, with a sleeve of the signal line. An example hereof is theintegration of the at least one rigid component with the sleeve of thesignal line. In yet another preferred variant, the gripping means areprovided with at least one holding member for coupling to an object tobe monitored. Here must be envisaged for instance openings in whichtiles can be placed, such that contact with the tiles is transmitted bymeans of the gripping means to the signal line. The holding member willherein usually be located on the side of the gripping means remote fromthe side of the gripping means that is connectable to the signal line.

The present invention also provides a signal line of the type mentionedin the preamble, characterized in that the signal line is provided withat least one of the gripping means as described above. In addition toutilizing separate gripping means, it is also possible within the scopeof the present invention to directly provide the signal line with thegripping means. It thus becomes possible for instance to use a finishedsignal line, i.e. a signal line with gripping means already placed orincorporated. It is desirable here that the signal line passes in asmooth line through the gripping means. In the unloaded situation of thegripping means such a relationship of signal line and gripping meansdoes not impede passage of the signal at all. The maximum length of thesignal-carrying line is not therefore limited by the gripping means.

In order to prevent for instance undesired disconnection of the grippingmeans from the signal line, the gripping means can be connectednon-releasably to the signal line. This is the case for instance whenthe gripping means form part of a sleeve enclosing the signal line. Thisembodiment variant also makes it possible to construct a sensitivesignal line in very advantageous manner.

The invention also provides an assembly manufactured from a flexiblematerial provided with gripping means for a signal line as describedabove, wherein the at least one rigid component is assembled with theflexible structural element. Instead of combining the gripping elementswith the signal line, it is also possible to combine them with thestructural element in which the signal line is placed. An additionaladvantage of such a structural element is that it enables an easycoupling to the signal line of a construction in which detection isdesired. Particularly envisaged here is a structural element in the formof a flexible sealing element, such as a rubber bumper, a rubber sealand so on.

The present invention will be further elucidated on the basis of thenon-limitative embodiments shown in the following figures, in which:

FIG. 1 shows a view of a first variant of a rigid component forming partof a gripping means according to the invention,

FIG. 2 shows a view of a second variant of a rigid component formingpart of a gripping means according to the invention,

FIG. 3 is a view of a third variant of a rigid component forming part ofgripping means according to the invention,

FIG. 4 shows a cross-section through a gripping means according to theinvention,

FIG. 5 shows a cross-section through a second variant of a grippingmeans according to the invention,

FIG. 6 shows a cross-section through a signal line according to theinvention,

FIG. 7 shows a cross-section through a second variant of a signal lineaccording to the invention, and

FIG. 8 shows a cross-section through a third variant of a gripping meansaccording to the invention.

FIG. 1 shows a rigid component 1 in a block form in which is arranged anopening 2 through which a signal line can be passed. For this purpose aline has to be pulled through opening 2. The rigid component 3 shown inFIG. 2 is likewise provided with a continuous opening 4 for receiving aline. A feed channel 5 connects onto opening 4 in this variant so thatthe rigid component 3 can be clicked onto a line in simple manner, atleast in the case the dimensions of the line and rigid component 3 areadapted to each other. FIG. 3 shows yet another variant of a rigidcomponent 6 in the form of a ball with a central opening 7 for receivinga signal line. When they grip onto a signal line, each of the rigidcomponents 1, 3, 6 can be embedded in a flexible sleeve not shown inthese figures, which flexible sleeve can then function as a springelement. When a rigid component 1, 3, 6 is loaded, it will be pressedfrom a starting position into the resilient sleeve, wherein a local loadwill simultaneously be exerted on the signal line. When the load hasdisappeared, rigid components 1, 3, 6 are urged back to the startingposition again by the resilient sleeve.

The gripping means 8 shown in FIG. 4 can for instance be applied tosupport tiles 9. Gripping means 8 is provided with an opening 10 forreceiving a signal line (not shown). In the case of an uneven load onthe tiles 9, the upper flat part 11 of gripping means 8 will rotate. Theconsequence is that an upright part 12 which supports the upper flatpart 11 will also deform. Deformation of the upright part 11 has aneffect on the signal line fed through opening 10. In this variant of thegripping means, the rigid component is formed by the materialsurrounding the opening 10, while the spring element is formed byupright part 12. The rigid component and spring element 12 are thus madefrom a single material part; the different characteristics are notobtained in this embodiment by using different types of material butrather by the design of the material, which results in the rigidcomponent around opening 10 and the spring element 12.

FIG. 5 shows yet another gripping means 13 in the form of a ‘pushbutton’. A holder 14 is provided with a receiving space 15 for a signalline; holder 14 forms a rigid component. Also lying against the signalline is a push button 16 that has a rounded head 17 that protrudes aboveholder 14; push button 16 also forms a rigid component. In order tobring the line into a non-deformed state in an unloaded position of thepush button 16, there is placed in gripping element 13 a resilientelement 18 with which in an unloaded position the push button 16 ispressed outward (out of holder 14) such that a signal line (not shown)placed in receiving space 15 is not loaded, or only loaded to a verylimited extent, by holder 14 and/or push button 16.

FIG. 6 shows a signal line 19, for example in the form of a glass fibrecable 19, which is provided with a protective sleeve 20. Sleeve 20 isprovided on the outside with gripping elements 1, 3 in the form of rigidcomponents as already shown in FIGS. 1 and 2. The signal line 21 shownin FIG. 7 is provided with a sleeve 22 into which rigid components 23are integrated in the form of thickened sleeve parts. Although thisvariant is also conceivable, it is recommended that the thickened sleeveparts are embodied separately from the sleeve (and optionally assembledwith the sleeve later); it is then after all more a case of an edgegripping the signal line. Depending on the circumstances however, thevariant of the signal line as shown in FIG. 7 can also be envisaged, forinstance if sleeve 22 takes a relatively thin form at the non-thickenedpositions. For proper operation of signal lines 19, 21 it is desirablethat they be supported in resilient manner. This is for instancepossible by placing signal lines 19, 21 on a resilient material layer orby arranging a sleeve manufactured from a resilient material around theillustrated signal lines 19, 21.

Finally, FIG. 8 shows a gripping means 24 in the form of a rubber seal,for instance for a door, made of a flexible material in which isarranged a passage 25 for a signal line. More rigid gripping elements 26are integrated into structural element 24 so as to increase thesensitivity of a signal line placed in structural element 24. As avariant it is also possible for the more rigid gripping elements to bemanufactured from the material of which the rubber seal is made, whereina greater rigidity is imparted to gripping elements 26 solely due to theshape thereof.

1-18. (canceled)
 19. Gripping means for a signal line, which signal lineis embodied such that the signal that is fed through the line can beinfluenced by loads exerted externally on the cable, which grippingmeans comprise at least one rigid component adapted to grip on thesleeve of the signal line, wherein the gripping means also comprise aspring element engaging on the rigid component to remove the load of therigid component from the signal line.
 20. The gripping means as claimedin claim 19, wherein the spring element is adapted to exert a biasingforce on the rigid component and directed away from the signal line whenthe rigid component is displaced to the signal line.
 21. The grippingmeans as claimed in claim 19, wherein the spring element is manufacturedfrom a flexible material.
 22. The gripping means as claimed in claim 19,wherein the spring element is embodied as a resilient sleeve in which atleast one rigid component is placed.
 23. The gripping means as claimedin claim 19, wherein the spring element is disposed between two rigidcomponents to be pushed apart by the spring element, between whichcomponents the signal line is placed.
 24. The gripping means as claimedin claim 19, wherein the gripping means are provided with connectingmeans for fastening the gripping means to the signal line.
 25. Thegripping means as claimed in claim 19, wherein the rigid component has ahardness between 10 and 100 Shore, preferably between 25 and 75 Shore.26. The gripping means as claimed in claim 19, wherein the springelement has a hardness less than 60 Shore, preferably less than 40Shore.
 27. The gripping means as claimed in claim 19, wherein thegripping means are positioned such that an edge of the rigid componentis positioned at least substantially at right angles to the centre lineof the signal line.
 28. The gripping means as claimed in claim 19,wherein the gripping means are releasable from the signal line.
 29. Thegripping means as claimed in claim 19, wherein the gripping means are atleast partially combined with a sleeve of the signal line.
 30. Thegripping means as claimed in claim 19, wherein the gripping means areprovided with at least one holding member for coupling to an object tobe monitored.
 31. The gripping means as claimed in claim 30, wherein theholding member is located on the side of the gripping means remote fromthe side of the gripping means that is connectable to the signal line.32. A signal line embodied such that a signal that is transmittedthrough the line can be influenced by loads exerted externally on thecable, wherein the signal line is provided with at least one of thegripping means as claimed in claim
 19. 33. The signal line as claimed inclaim 32, wherein the signal line passes in a smooth line through thegripping means.
 34. The signal line as claimed in claim 32, wherein thegripping means are connected in at least a partially non-releasablemanner to the signal line.
 35. The signal line as claimed in claim 32,wherein the rigid component forms part of a sleeve enclosing the signalline.
 36. The signal line as claimed in claim 32, wherein the signalline is embodied as a flexible sealing element.